Author Topic: Slideshow on a PCW  (Read 1666 times)

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Offline GeoffB17

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Re: Slideshow on a PCW
« Reply #25 on: 18:38, 19 May 20 »
Hmm, should this be 32 lines, rather than 30?   So each tile is 1 byte wide, and 8 lines high (8x8 bits)?  So if I'm starting with .BMP type data, already inverted bottom to top, I need the first byte from the first line followed by the first byte of the second line .... first byte of the 8th line followed by the 2nd byte of the first line .... 2nd byte of the 8th line followed by the 3rd byte of the first line... etc?   I'll try to see how that fits with how my file shows on the screen, but it could tie up.

Geoff

Offline OliW

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Re: Slideshow on a PCW
« Reply #26 on: 19:17, 19 May 20 »
This code snippet from the convertor probably explains it better than words...
Code: [Select]
for y0 in range(kYDimDiv8):
for x0 in range(kXDimDiv8):
for y1 in range(8):
byte = 0
for bit in range(8):
y = (y0 << 3) + y1;
x = (x0 << 3) + (7 - bit);
if im.getpixel((x,y)) != 0:
byte = byte | (1 << bit)
data.append( byte )
It follows the memory layout of the PCW, which is in character blocks.  8 consecutive bytes are stacked vertically.
- Oli Wright

Amstrad PCW8256, Amstrad CPC464
Also VIC 20 x2, C64, BBC Master, A500, A500+, Electron, Atari 130XE

Offline OliW

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Re: Slideshow on a PCW
« Reply #27 on: 19:28, 19 May 20 »
Ah - I missed your previous post.  Yes - you've got it.  I'm making SPC files that are 720x256, so that's 32 character rows high - yes.
- Oli Wright

Amstrad PCW8256, Amstrad CPC464
Also VIC 20 x2, C64, BBC Master, A500, A500+, Electron, Atari 130XE

Offline GeoffB17

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Re: Slideshow on a PCW
« Reply #28 on: 19:44, 19 May 20 »
Thanks,

Yes, I'm comparing the data in the .BMP I made, where the data starts at the end of the file, to .SPC that I created on the line-by-line format, and the version made by your process, and the data ties up.   I can see the pattern.   I just need loops within loops and build up 8 lines at a time from the .BMP data and it should work.   Touch wood!   Important thing, the .BMP data is essentially correct, just in completely the wrong order!

Geoff

Offline GeoffB17

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Re: Slideshow on a PCW
« Reply #29 on: 00:34, 20 May 20 »
Hello Oli,

Right, made some changes to my QB prog, rearranged the loops, and just recompiled and run.

Seems to have produced a file that looks much better.   The 'patterns' of the data looks just like your version, and totally NOT like my previous version.  Still got the same file size!   I'll get it copied over to the PCW via floppy disk and test it.

Oh, I attach the two further 'slides' I've made so far.   The TEAC one is one of my big tape recorders, the original photo for this was taken with the Sony Mavica 640x480 resolution.   The other pic was a pic I've had on my computer since early 90s, I'm sure it wi;; have been a print photo then scanned, NOT I'm sure taken as a digital photo, but I've always had a soft spot for the image!

Later.. Just tried the latest product of my conversion prog, and this one is working fine, so the info regarding the format of the .SPC file is correct.  Thanks

Geoff
« Last Edit: 02:30, 20 May 20 by GeoffB17 »